I have been fishing with the floor mounted seat on the lakes and rivers. It has no effect on the stability of my particular kayak. The big win is that I have not experienced any back pain in this lower position either. I do enjoy the fishing experience when I sit up higher but it was not necessary to relieve the stress on my back.

One thing I did have to do early on was go to bigger screws. I installed 1 inch, #14 wood screws and that stabilized the mount.